Whatever you use, make sure it's clear what you mean: i.e. the `1GB = 1 billion bytes and 1TB = 1 trillion bytes` type footnote used on sales pages for products

Whatever you use, make sure it's clear what you mean: i.e. the `1GB = 1 billion bytes and 1TB = 1 trillion bytes` type footnote used on sales pages for products with a storage component. Consider who the target audience is. Technical users will know (or should at least understand if you provide more details) GiB, but non technical users are much more likely to understand GB.